The invention relates to folding keyboards, and in particular to a folding keyboard particularly useful for use with a personal digital assistant.
Personal digital assistants (xe2x80x9cPDA""sxe2x80x9d), such as the devices manufactured by PALM(trademark) and HANDSPRING(trademark), are popular both as portable computers and as wireless communication devices. These devices use a pen to either hand-write characters or select letters from a simulated keyboard. However the lack of a standard keyboard greatly reduces the usefulness of these devices for word processing, e-mail, internet access or software applications. Touch typists require a standard size keyboard to type at full speed and efficiency. This requires a standard key size of about 18 mm square, with a 1 mm spacing between keys. Thus a standard size keyboard cannot be reduced to a size comparable to the size of a PDA without folding and/or collapsing the keyboard.
A collapsible full-size keyboard has been developed for PDA""s and similar devices. See for example U.S. Pat. No. 6,174,097 issued Jan. 16, 2001 to Simon entitled xe2x80x9cCollapsible Keyboardxe2x80x9d, which keyboard is sold under the trademark STOWAWAY by Think Outside, Inc. While such a device provides a collapsible full-size keyboard for a PDA, it is complex to manufacture due to the need for three folding axes and multiple slidable keys and spring connections to effect collapsing. It is also larger than the PDA when collapsed. Before one can use the STOWAWAY keyboard, a driver program must be installed on the PDA. To connect the PDA with the STOWAWAY keyboard, a popup stand to support the PDA is provided on the keyboard. The connector of the PDA is slid onto a corresponding connector on the keyboard.
The present inventor has invented a folding keyboard which allows a full-size keyboard to be folded using a split key, as disclosed in U.S. Pat. No. 6,088,220 issued Jul. 11, 2000. However such a keyboard, while useful for a pocket-sized computer is also greater in size than a PDA when folded.
The present inventor has also invented a combination mobile telephone, personal digital assistant and computer, as disclosed in provisional application No. 60/219,125 filed Jul. 19, 2000 which comprises a computer keyboard comprising a plurality of keys generally corresponding to the keys of a standard personal computer keyboard, and comprising two halves hingedly connected along a fold line extending transversely across the keyboard, each half thereby comprising a portion of the plurality of keys, whereby the computer is folded from a first open position in which the plurality of keys forms the generally standard personal computer keyboard, to a closed position in which the two halves are in opposed parallel relationship whereby the respective portions of the plurality of keys on the respective halves face each other in close proximity or actual contact, and which includes keys which are reduced in size but act like regular sized keys due to the shape of the key surface.
There is therefore a need for a folding keyboard for use with PDA""s which functions as a full-size keyboard and which folds in a simple manner to the size of a PDA.
The present invention provides a folding keyboard comprising a plurality of keys generally corresponding to the keys of a standard personal computer keyboard comprising three parallel, lengthwise rows of keys comprising a central row, an upper row and a lower row, and comprising two halves hingedly connected along a fold line extending transversely across said keyboard perpendicular to the direction of the rows, each half thereby comprising a portion of said plurality of keys, whereby the keyboard is folded from a first open position in which the plurality of keys forms a generally standard personal computer keyboard, to a closed position in which the two halves are in opposed parallel relationship; and wherein the central row comprises keys of standard size, and the upper and lower rows comprise keys which are reduced in size in the transverse direction. Preferably the surfaces of the upper and lower rows of keys and the keys at either ends of the rows are configured to redirect a typist""s finger to the center of the reduced size key.